The Potion
by LadyEmrys15
Summary: Arthur is in need of an heir, and the boys get inventive. One-Shot, KKM Fill, MPreg.


**Title: The Potion**

**Author: Lady_Emerys/LadyEmrys15**

**Rating: Mature (I think that`s the right rating)**

**Author's Note: Hi, I just wanted to warn you guys that this is pretty much my first attempt at smut, let alone slash fiction. If it's sucks, and not in the good way, please refrain from using pitchforks on me. This was also a KinkMe Merlin fill for LJ.**

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><p>Merlin stared at the potion in apprehension. To put it mildly, the concoction smelled like shit.<p>

It would undoubtedly taste like shit as well.

And he had to be the one to drink it.

Fun...

Honestly, the things he did for Arthur went above and beyond the call of duty. Ah, well... I guess that's what happens when you're in love with a king. You get stuck with the short end of the stick. Not to be misunderstood, Arthur's stick was anything but short – or small.

It was big, and long, and when Arthur swivelled his hips just right...

Um, we're getting a bit off track here.

Anyways, Arthur's _stick _was more than adequate, and he sure as hell knew how to use it right. You could take Merlin's word for it. If anyone would be aware of the king's sexual prowess, it would be the sorcerer himself. After all, he had spent the past three years sharing Arthur's bed.

Which now led Merlin to the situation at hand.

The potion...

A potion which would allow him to carry King Arthur's heir.

Arthur paced their room backwards and forwards for the hundredth time. He was a little anxious about the entire idea. However, he couldn't deny that the idea held a certain appeal. To have Merlin – his sorcerer, his lover, his consort – to have Merlin, and to have him carry his heir...

The very idea made him deliriously happy. One might even venture to say that the king preened with glee.

Arthur raked his hand through his roughly dishevelled hair, "Is it almost ready?"

"Nearly done," Merlin sighed at his lover's nervous fidgeting. Arthur had been acting this way for the better part of an hour, and it was really starting the get on the warlock's nerves, "Would you stop that? You're becoming very annoying."

King Arthur froze mid pace, and scowled at the sorcerer currently bent over a boiling cauldron, "My apologies Merlin, I didn't realize I was making such a nuisance of myself."

Merlin simply rolled his eyes. He never responded well when Arthur was being sarcastic. The king huffed at the sorcerer, making his distaste evident. When his lover failed to retort, Arthur took up his nervous pacing once more.

Merlin sighed, "Look, I know you're anxious about this, but you need to stop. You're starting to break my concentration. If you keep going on like this I might end up having to start from scratch."

Arthur paused, "from scratch?"

The sorcerer snorted, "From scratch."

The king abruptly stopped pacing after that.

Twenty minutes had passed, and the potion still wasn't ready. Since he'd all but been forbidden to pace, the king attempted to act nonchalant about the entire thing, but it just wasn't working as well as he had hoped. With nothing better to do, Arthur began to look over the books and parchment strewn about the room, all of which were remnants' of the late court physician Gauis.

Unbeknownst to the king, his fingers began drumming against a shelf of their own accord.

"Arrr-thurrr!" Merlin screeched.

The sorcerer smirked as he corked the small vial, and lifted the potion up and into the light for further expression, "it's done."

Arthur, who had been nodding off in a chair located in the far corner of the room, jumped up in surprise. Half asleep, his eyes scanned the room for any potential threats, his body in a defensive stance. His brow scrunched in confusion, "huh, what?"

Merlin stared incredulously at the king. Sometimes he still wondered what had ever possessed him to fall in love with such a... clotpole. The sorcerer rolled his eyes, "Arthur, the potion."

King Arthur stared at him with a vacant expression.

Exasperated, Merlin waved the potion in his lover's face, "the potion, it's ready."

Arthur smiled.

It reminded the sorcerer of just why he was in love with the king of Camelot. Arthur might act like a jerk sometimes – okay, most of the time, but he was there when it counted the most. In truth, the king did have a rather sensitive side when he allowed himself to show it.

...But then the great prat had to ruin the moment as usual.

"It's about bloody time! What in the hell took you so long to make this?" Arthur prostrated, hands flung up the air, posture and tone incredulous.

Merlin took it back; Arthur was nothing more than an enormous clotpole.

Really...

Merlin downed the potion in one shot. He almost chocked on it near the end, but he managed to hold it down. However, he wasn't able to hold back the disgusted grimace that settled upon his face. He stood by his potion, it would do what he needed it to do, but did it ever taste like shit!

"Well," Arthur clapped his hands together. For once, the king was unsure as to how to proceed, "that's it?"

"That and you have to cum inside me as often you can," the sorcerer grinned, challenge stated.

A confident smirk overcame King Arthur's face, "oh, I doubt that will be a problem."

Merlin looked thoughtful for a moment, "I don't know Arthur. Are you sure you can handle it?"

The blonde stared agape at his lover, his nostrils flaring slightly, "you're going to regret saying that."

The sorcerer gulped.

Arthur gazed down at his lover, a cocky smirk on his face.

Merlin lay face down on the bed, withering, as Arthur kneeled above him. Three of the king's fingers were coated with oil, and currently pumping in and out of his lover's tight little bottom.

He loved seeing Merlin like this, wanton and gasping. The sorcerer was moaning and groaning, and Arthur loved every second of it... There'd be no denying it. After tonight, Merlin would be his and his alone. No one would take the sorcerer away from him; Arthur would make sure of it.

And once Merlin bore him an heir...

Merlin whined, protesting when Arthur withdrew his fingers. He had been so close.

Arthur smirked, grabbed his lover's hips, and sunk into Merlin's tight flesh.

They moaned in unison, and the bed began to creak in earnest.

It would be a miracle if the bed survived the night.

Merlin awoke with a dazed smile the next morning. Arthur's arms were wrapped around his torso in a protective, and possessive embraced.

The sorcerer broke out into a wide grin. He could already feel it – it was fluttering inside his body.

Merlin was carrying Arthur's heir.

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><p><strong>Okay, so this was a one-shot, and I hope somebody out there liked it. <strong>


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